Operating
and
Installation
instructions
8
Feedback
selection
Figure
5.
Two
feedback
types
for
amplitude
control
of
the
oscillator
are
available.
Either
‘PRIM.’:
feedback
of
the
primary
voltage
to
the
transducer
(default
setting),
or
‘SEC.’:
feedback
of
the
mean
value
of
the
transducer
secondary
voltages.
Set
switch
SW2
on
the
circuit
board
accordingly.
Certain
transducers
are
manufactured
with
linearization,
which
makes
the
mean
value
of
the
secondary
voltages
dependent
on
the
core
position.
These
transducers
must
be
used
with
feedback
type
‘PRIM.’.
Transducers
for
which
the
mean
value
of
the
secondary
voltages
is
independent
of
the
core
position,
within
the
linear
range,
can
be
used
with
feedback
type
‘SEC.’.
Check
that
the
oscillator
output
doesn’t
exceed
6
V
AC!
Feedback
type
‘SEC.’
gives
a
considerably
reduced
influence
on
the
measurement
from
temperature
variations
and
cable
length.
Calibration
General
The
two
channels
are
identical,
so
the
calibration
is
carried
out
in
the
same
way
for
both
channels.
Adjusting
the
zero
point
Figure
5.
For
a
position
transducer,
type
LVDT,
the
core
centre
position
is
an
accurate
reference
point.
It
should
correspond
to
the
centre
of
the
output
signal
range
(0
V
for
bipolar
and
+5
V
for
monopolar
voltage,
12
mA
for
current
loop).
Setting
of
this
zero
reference
point
should
be
performed
in
four
steps:
STEP
1:
Set
the
amplifier
gain
in
medium
range
by
the
switches
SW1:
SW1,
no.1
and
no.3
to
OFF,
SW1,
no.2
to
ON.
Then
adjust
the
transducer
core
to
an
approximate
centre
position.
(This
will
bring
the
AC
voltage
between
test
sockets
Sec.
1
and
Sec.
2
close
to
0
V.
If
not,
the
transducer
connection
is
probably
not
correct;
one
of
the
secondary
coils
must
be
phase
reversed.)
STEP
2:
Connect
test
socket
Sec.
1
to
Sec.
2.
Then
use
potentiometer
Bal.
to
adjust
the
output
signal
to
the
centre
of
its
range
(0
V,
+5
V,
or
12
mA).
STEP
3:
Adjust
the
moving
machine
component
to
the
required
centre
position.
STEP
4:
Remove
the
connection
Sec.
1
to
Sec.
2.
Then
adjust
the
transducer
core
mechanically,
without
changing
the
machine
part
position,
to
bring
the
output
signal
to
the
centre
of
its
range
(0
V,
+5
V,
or
12
mA).
Fine
adjusting
of
the
zero
reference
point
may
be
necessary
after
changing
the
gain
setting.
Summary of Contents for LVD 3
Page 1: ...Op Ins erati tallat ng a tion i and instru LVDT uctio T Sig ons nal co onditi LV oner D 3 GB ...
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Page 14: ...Operating and Installation instructions 10 ...
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Page 23: ...LVDT Sign A De nal Condition ppendix 2 eclaration o ner LVD 3 2 of Conformi ity ...
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